Isa Koi Farm

Isa Koi Farm is a Showa farm. Hajime Isa founded it in Ojiya, Niigata in 1970, his son Mitsunori runs it now, and roughly 70 percent of what comes out of the ponds is Showa, with Kohaku and Sanke making up the rest. ChampKoi imports koi from Isa, and their Showa are the reason to buy.

What an Isa Showa gives you is frame. The old assumption in the trade was that Showa were stocky fish that topped out smaller than Kohaku or Sanke. Isa bred against that, and their Showa now reach about 80 cm while keeping their shape; one of the farm's parent fish is a Maruten Showa of 101 cm. The sumi is the other tell. Isa selects for black that shows early and a pattern that does not drift much between tosai and adult, so what you see in the bowl is close to what you will own in four years.

The show record backs this up. Isa Showa have taken the Kokugyo prize at the All Japan Nishikigoi Show more than once. The farm's Kohaku are no afterthought either: an Isa-bred 85 bu Kohaku owned by Benedict Campos won Grand Champion at the 2nd World Nishikigoi Show in Mihara, Hiroshima in November 2025, and an Isa-bred 80 bu Kohaku of his took Superior Champion at the 55th All Japan Nishikigoi Show.

The farm runs 31 mud ponds on about seven hectares around Ojiya, filled with mountain snowmelt, and Mitsunori credits the soil in each pond for what it does to skin and sumi. Isa is a Gosanke house. If you are after Chagoi, metallics or kawarimono, look at another farm on our list; if you want a Showa that will still be getting better at 70 cm, start here.